Monday, October 24, 2011

R. Aharon Kotler's BMG-Lakewood brainteasers.[1]

Rabbi Aaron Kotler, the famous Rosh Yeshiva, used to set puzzles for prospective students at his Yeshiva to test what we today call their IQ. One of these was: prove which of the following two statements is true and which is false. (1) No two people on earth have exactly the same number of hairs on their head. (2) There are people on earth with exactly the same number of hairs. The proof that (1) is false is, of course, that since there are billions of people on earth it is impossible for everyone to have a different number of hairs - that would mean that there are people with millions of hairs on their head and clearly there are no such people.

A similar puzzle which I heard had been set by R. Aaron Kotler to test his student' ability to deal with problems was already familiar to me from the 'Japes and wheezes' column in my boyhood comics. A lily pond doubles itself each day and in 28 days the pond is full. How long does it take for the pond to be a quarter full? The answer is, of course, 26 days, not, as most people reply, seven days.

In Helping With Inquiries; An Autobiography (London, 1989) by Louis Jacobs, pg. 72.

[1] Actually I have no idea if this was in Lakewood, or Kletzk. See this post about R. Haim Joseph of Baghdad's brain teasers for sharpening the mind of youths.

Anyway, this isn't yesterday's coffee room stuff, at least not exactly. This is what a guy who was born in 1923 says he heard. Whether he heard it firsthand from someone who was asked these things) or secondhand, I cannot say.

In any case, you can ask the same question on the Ben Ish Chai, and no doubt you would ask it except that his book is the proof that he did put down such puzzles.

S: "Anyway, this isn't yesterday's coffee room stuff, at least not exactly. This is what a guy who was born in 1923 says he heard."

I don't see these as a contradiction.

Most of what you hear nowadays, about things in our own time, is false. Louis Jacobs was far removed from Lakewood circles, for the most part. He was probably repeating some third-hand jive he heard floating around.

"In any case, you can ask the same question on the Ben Ish Chai, and no doubt you would ask it except that his book is the proof that he did put down such puzzles."

I would not ask it. It's well known that R' Chaim Brisker used to ask his son (the BR) such types of questions (e.g. figure out how many bricks are in that building), also in order to sharpen his mind.

This stuff is useful for younger kids, to develop their minds. It's not something you would do as a test, for older students who would be expected to have serious exposure to Torah concepts already.

I don't believe R. Ahron Kotler gave this brain teaser because the answer is so simple. This question is more appropriate for children, not bachurim that were listening to the great shiruim of R. Aharon.